Rotating display constructions

ABSTRACT

A display construction wherein a motor is employed for moving at least portions of the display. The motor is connected to a drive member which continuously rotates relative to a display support. A drive connection between the motor and display support is adapted to be intermittently and automatically removed whereby the display will have intermittent rest periods. The intermittent drive is controlled by means of a cam member which periodically forces a stop member out of contact position relative to the display support whereby the motor will drive the display support until the contact is re-established.

United States Patent Poulos ROTATING DISPLAY CONSTRUCTIONS Primar E.ranzinerJohn H. Wolff 76 I t G P l,3020P lt., l 1 nven or s t gfi 22;; m ear S Attorney, Agent, or FzrmMcDougall, Hersh & Scott [22] Filed: Sept. 14,1973 [57] ABSTRACT [21] App]. No.: 397,449 A display construction wherein a motor is employed for moving at least portions of the display. The motor [52] U 5 Cl 40/33 40/49 40/106 3 is connected to a drive member which continuously [51] m G09f 11/1'0 rotates relative to a display support. A drive connec- [58] Fieid 77 106 52 tion between the motor and display support is adapted 106 to be intermittently and automatically removed whereby the display will have intermittent rest peri- [56] References Cited ods. The intermittent drive is controlled by means of a cam member which periodically forces a stop member UNITED STATES PATENTS out of contact position relative to the display support 1.810,!61 6/1931 Conklin 40/33 whereby the motor will drive the display support until 2,117,882 5/1938 Going 40/33 the Contact is reestablished. 2,839,855 6/1958 Palmer et al 40/33 3,774,329 11/1973 Horowitz 40/33 14 Claims, Drawing Figures L l T l l I l l l l l 4' I 43 I4 "l'l' 28 30 7 i f *6 t 41 5- z ll 42 5- 20 7 l i l 7 7 US. Patent Nov. 11, 1975 Sheet10f4 3,918,183

US. Patent Nov. 11, 1975 Sheet 3 of4 3,918,183

1 1G014 i E6115 US. Patent Nov.11,1975 Sheet4of4 3,918,183

FIG, 20

ROTATING DISPLAY CONSTRUCTIONS This invention relates to display constructions. The invention is particularly concerned with constructions utilized for retail purposes, for example, point of purchase" displays designed to attract retail buyers.

It is well known that advertisingdisplays must be at tractive in order to be effective particularly where many such displays are located in the same general area. It is also recognized that the provision of motion in advertising displays lends to the attractiveness thereof.

Displays which have motion characteristics must also have certain unique features in order to appeal to the advertising industry. In addition, it is necessary to provide displays which are economical to produce and operate so that the expense of the displays does not prevent practical use. This is particularly true where a large number of the displays are being used to promote a product or products in many different stores.

It is a general object of this invention to provide a display construction which is characterized by unique motion features whereby the construction is particularly adaptable for use as a point of purchase display or for other advertising purposes.

It is a further object of this invention to provide a display construction of the type described which is particularly characterized by an efficient design and mode of operation whereby the display advantages can be achieved at a relatively low cost.

These and other objects of this invention will appear hereinafter and for purposes of illustration, but not of limitation, specific embodiments of the invention are illustrated in the accompanying drawings in which:

FIG. 1 is an elevational view of display mechanisms incorporating features of the invention;

FIG. 2 is a side elevational view of the arrangement shown in FIG. 1;

FIG. 3 is an elevational view of the structure shown in FIG. 1 having the energy seal section partly cut away and illustrating the stop action mechanisms in a different position;

FIG. 4 is a plan view of the structure taken about the line 44 of FIG 1;

FIG. 5 is a cross-sectional view taken about the line 5-5 of FIG. 1;

FIG. 6 is a cross-sectional view taken about the line 66 of FIG. 1;

FIG. 7 is a cross-sectional view taken about the line 77 of FIG. 1;

FIG. 8 is an elevational view, partly cut away, illustrating a modified form of the invention;

FIG. 9 is a side elevation of the structure shown in FIG. 8;

FIG. 10 is a cross-sectional view taken about the line 10l0 of FIG. 8;

FIG. 11 is a cross-sectional view taken about the line llll of FIG. 8;

FIG. 12 is an elevational view of a further modification of the invention;

FIG. 13 is a detailed sectional view of the structure shown in FIG. 12;

FIG. 14 is an elevational view ofa still further modifi cation of the invention;

FIG. 15 is an elevational view of another alternative form of the invention;

FIG. 16 is a cross-sectional view taken about the line l6l6 of FIG. 15;

FIG. 17 is an enlarged cross-sectional view taken about the line 17-17 of FIG 16;

FIG. 18 is a bottom view of the drive plate structure utilized in the arrangement of FIG. 15;

FIG. 19 is a plan view of a disc protion utilized in the structure of FIG. 15; and,

FIG. 20 is a side elevational view of a modified arrangement for achieving drive movement for displays.

This invention generally relates to a display construction wherein a motor is provided for imparting movement to a support which constitutes or carries the display. The invention is particularly concerned with the provision of an arrangement including a continuously operating motor with means interposed between the motor and the support so that an intermittent display motion is achieved.

The particular means for transmitting movement to the support comprise a cam carried by a drive member connected to the motor. At least one first stop member is carried by the display support, and at least one second stop member is mounted adjacent the support. The second stop member is movable between an engaging position in the path of movement of the stop member carried by the support and a position away from this engaging position. The continuously rotating cam regularly contacts the second stop member to move the second stop member away from the engaging position in response to movement of the cam. Accordingly, the display support is free to move each time the associated first stop member is released by the second member while the support is held stationary at intermediate stages thereby providing the desired intermittent movement of the display.

The accompanying drawings illustrate various forms of the invention which incorporate the features referred to. In the embodiment shown in FIGS. 1 through 7, the structure includes a tubular housing 10 provided for holding a pair of batteries 12. In conventional fashion, a spring 14 urges'the batteries upwardly whereby the contact 16 of the-upper battery is adapted to engage a contact l8-which is provided for the motor 20. This motor is supportedon a yoke 22 which is pivotally connected to the-battery housing 10 at 24. As best shown in FIG. 2, this-permits movement of the motor 20 away from the end of the housing for battery replacement purposes.

The motor 20 operates a drive shaft 26 which is connected to a continuously rotating drive plate 28. This drive plate 28 carries ,a downwardly extending cam 30.

A stop member 32 is;located in the path of movement of the cam 30. This stop member, as best shown in FIG. 5, defines an over-sized hole 34 which receives the drive shaft 26 whereby-the drive shaft confines the stop member while being free to rotate relative thereto. The stop member includes a-second opening receiving a pin 36, and this pin is reciprocally received by an opening 38 defined by outwardly extending ear 40 formed integrally with the motor 20. A piece of rubber or other resilient material 42 receivesthe pin 36, and this member is located between the ear 40 and the stop member 32 to thereby mormally hold the outer end of the member 32 in the raised position as shown in 'FIG. '1.

A display support plate 44 is provided for carrying any suitable display 46. The plate 44 carries three downwardly extending stop pins 48, these pins being spaced l20apart. As shown in FIG. 1, these pins, when rotated along with the plate 44, will move into engagement with the stop member 32. Thus, the stop pins prevent rotation of the drive plate 44 as long as thestop member 32 is positioned as shown in FIG. 1.

THe cam 30 operates to drive the member 32 downwardly for releasing the display support plate. Thus, the cam 30 drives the member 32 out of engagement with a pin 48 leaving the display support plate free to rotate. The movement of the drive member 28 may be transmitted to the drive plate by means of a friction disc or any other mechanism which will automatically transmit movement from the drive plate to the display support 44 as soon as the stop member 32 and a stop pin 48 become disengaged.

In view of the size of the cam 30, the stop member 32 is restored to its blocking position by the resilient element 42 before the rest stop pin 48 arrives at the position of the stop member 32. Accordingly, the display will rotate only 120 before again being held by a stop member, and the display will remain in this position until the cam 30 completes the next revolution. Obviously, many variations of this arrangement are feasible while following the concepts of the invention.

FIGS. 8 through 11 illustrate one possible variation embodying the concepts of the invention. In this instance, the battery housing 50 is located within the confines of a section of a pole 52. This pole may be of any standard variety employed as a support for various commercial purposes. The housing 50 may be dimensioned to fit within a pole and to then be separately supported, for example by means of a ledge contacting the base of the housing. On the other hand, the pole and/or housing may be dimensioned so that the housing could be forced into the body of the pole and thereby held in position during use.

The motor 54 defines a contact 56 which engages the contact 58 of the upper battery 60. As in the case of FIG. 1, the motor drive shaft 68 is received in an opening defined in the base of stop member 64. A spring 66 is positioned around the shaft 68 of the motor, and this spring normally holds the stop member 64 in the upper or operating position shown in FIG. 8. Pin 62 held by the motor support serves to hold stop member 64 against movement due to rotation of shaft 68.

The structure includes a first display support 67 which may carry a downwardly extending display 70. A second display support 72 which may have an upper display 74 and/or a downwardly extending display 75 is linked to the support 67. The drive linkage is provided by means ofa bracket 76 mounted on the support 67 with a pinion 78 being rotatably mounted on the bracket. This pinion drivingly connects the gears 82 and 84. It will be appreciated that rotation of the gear 82 in one direction operates to rotate the gear 84 and its associated support in the opposite direction. An arrangement of this type provides a particularly unusual display arrangement while being quite efficient in design.

The drive shaft 68 for the motor 54 carries drive member 86, this drive member being connected to the drive shaft by means of set screw 88. A second shaft member 90, not connected with the drive shaft 68 is tied to the display support 67by means of set screw 92 received in the collar 94 whereby any rotation of the support imparts a corresponding rotation to the shaft 90. A set screw 96 secures the gear 82 to the shaft 90 so that any rotation of the shaft results in rotation of the gear 82 which, in turn, rotates display support 72 through pinion 78 and gear 84. The latter is not con nected to the shaft and is, therefore, free to rotate in a direction opposite the direction of shaft rotation.

It will be appreciated that the use collars and set screws provides a means for extending the shaft 68 whereby multiple displays can be built up. The shaft 68 could, however, be ordered longer to provide the same result.

The intermediate rotation of displays connected to the structures of FIGS. 8 through 11 is provided through the action of stop pins 98 and cam 100. These stop pins normally engage the stock member 64 while the cam member 100 depresses the stop member once during each revolution. Accordingly, the stop member when engaged by the cam will release a stop pin whereby the drive member 86 will rotate the support plate 67 through the use of a friction drive connection. As the cam passes the arm 64, the arm is restored to the stop position whereby the arm is again engaged with a stop pin. 90 of movement is, therefore, achieved during each cam revolution since, in this instance, four stop pins are provided on the display support 68.

FIG. 12 illustrates a modified arrangement wherein a motor housing has a drive shaft 112 extending outwardly thereform. This drive shaft extends suffuciently to provide for carrying ofa drive plate and a display support. Specifically, a collar 114 is tied to this shaft, and a drive plate 116 is connected to the collar for rotation therewith. Friction drive 118 is provided for immparting rotary movement to a display support 120.

The drive plate 116 carries a cam 122 which is adapted to engage a flexible strip 124 serving as a stop member. One end of the strip receives the drive shaft 112, and a spring 126 normally holds this end down whereby the opposite end of the strip extends upwardly into the path of movement of stop pins 128 carried by the support 120. The strip 124 engages posts 130 and is held in position on this post by means of pin 132. The cam 122 bends the strip downwardly during each revolution whereby one of the stop pins is released during each revolution with the next stop pin engaging the strip when the strip springs back. The display is, therefore, moved intermittently with the degree of movement during each revolution of the cam depending upon the spacing of the pins.

In FIG. 13, a motor is provided with a pinion 142 carried on drive shaft 144. This pinion engages gear 146 which is drivingly attached to plate 148. The plate 148 carries cam 150, and a stop member (not shown) is provided for engaging one of the stop pins 152 carried by the display support 154. A friction drive is employed as described, and the cam operates to disengage the stop member from a pin during each rotation of the cam. The arrangement of FIG. 13 thus illustrates the manner in which the principles of the invention can be utilized in a system having the motor drive shaft offset from the axis of rotation of the display support.

FIG. 14 illustrates an arrangement utilizing a drive mechanism similar to that of FIG. 13 wherein the motor is mounted on a plate 162 with the drive shaft of the motor being offset from the axis of display rotation. This drive shaft carries a pinion 166 which engages drive gear 168 carried by the drive plate 170. A friction drive connects this plate toadisplay support plate 172 Cam 174 is adapted to engage flexible strip 176 dur; ing each revolution of cam movement. This strip is attached to a collar 178 which is secured by means of set screw 180 to pipe 182. A post 184 mounted on. the plate 162 carries a flexible ring 186 and pin 188. The strip is confined between the ring and the head 190 of the pin whereby the strip is normally bowed upwardly into the path of movement of stop pins 192 carried by plate 172. The cam 174 operates to drive the strip downwardly into the dotted line position thereby disengaging the strip relative to a stop pin. The continuously rotating drive motor then imparts movement through drive plate 170 to the support 172 whereby this support will rotate until the next pin comes into engagement with the strip 176.

The pipe 182 provides a means for enclosing electrical leads 194 whereby the bulb 196 will serve to'ligh t' the display located on the plate 172. This pipe, there fore, serves as a convenient mounting means for the mechanisms illustrated while facilitating lighting of the display. It will be appreciated that the lighting of the display can be accomplished much more inexpensively than in the case of lighted displays utilizing rotary contacts for transmitting power. Thus, lighted intermit-. tent movement can be achieved with this arrangement in a highly efficient manner.

FIGS. through 18 illustrate a further modification of the invention wherein additional intermittent movements are accomplished. In this arrangement, a motor 200 includes drive shaft 202 which is connected todrive plate 204 by means of collar 206 and set screw- 208. This drive plate supports an additional plate 210v which is connected to the drive plate through a friction drive. The plate 210 defines three openings 212 which receive wheels 214. These wheels engage the top surface of the drive plate 204 and the wheels are adapted to rotate in response to movement of the drive plate.

The wheels are mounted on individual shafts*216 which are secured to a disc 218 which defines aii enlarged opening 220 whereby the disc is free to 1%.: heldin position as the shaft 202 rotates. Similarly, the opening 222 of the plate 210 permits relative movementbetween this plate and the drive shaft. One of the shafts 216 has a bent end 217 which extends into opening2 l9 defined by the plate 210 (FIG. 19). This ties the disc 218 and plate 210 together.

A stop arm 224 receives the shaft 202, and thisend of the arm is forced upwardly by means of spring 226. The drive plate 204 has a cam 228 secured thereto, and this cam is adapted to engage the arm 224 for depressing the arm as shown in FIG. 17. A pin 230 is carried on the outer end of the arm, and as shown in FIGS. 15 and 16, this pin is adapted to engage tabs 232 formed on the outer periphery of the wheel housing and display support 234. A stop pin 229 holds the arm 224 in a stationary position.

Additional tabs 236 are formed on the periphery of the plate 210, and these tabs are also adapted to be engaged with pin 230. As in the case of the previous e'mbodiments, the cam 228 moves the pin 230 outof engaging position once each revolution. g g

In the operation of the structure of FIGS. 15 through 19, the motor 200 rotates the drive member 204 and associated cam 228, and if the pin 230 is engaged with a tab 236, the plate 210 is held stationary. Similarly, if

the pin 230 is engaged with a tab 232 atthis time, the housing 234 is held stationary since the wheels 214 will not transmit any movement under the circumstances.

Whenthe cam'228 depresses the pin 230, the friction means between drive member 204 and plate 210 will cause rotary movement of this plate. This results in movement of any display associated with the plate 210. In addition, thewheels 2l4 will impart movement to the housing 234 and any associated display with this housing rotatingin a direction opposite the direction of movement of the plate 210.

As the cam 228 passes the arm 224, the pin 230 is raised to engaging position. This pin then remains in this positionuntil a tab 232 and a tab 236 encounter the pin whereby displays are held stationary until the carn 228 maltes the next revolution. Depending upon the spacing ofthe respective tabs, different relative rotary movements can be achieved. For example, twice asjmany tabs 232 could be employed so that the duratio nl of intermittent movement for the housing 234 would be shorter than the duration of movement for the plate 210.

FIG. 20 illustrates an additional modification of the invention wherein a motor 240 having drive shaft 242 is employed for moving a first display carried on support and a second display carried on support 246. The support 244 is tied to the shaft 242 by means of set screw 248 whereby this support moves continuously while the motor is running.

A drive disc 250 is tied to the drive shaft 242 by means of set screw 252 whereby this drive disc is also continuously rotated. A stop bar 254 defines an opening receiving the shaft 242, and a stop pin 256 serves to hold the bar in a stationary position thus avoiding movement of the barwhich might occur due to frictional engagement between the shaft and the bar. Spring urges the bar upwardly whereby the bar normallybears against the collar 260 formed integrally with drive disc 250.

a Afplurality of pins 262 extend downwardly from the display support246, andthese pins will engage the bar when the bar is in the position shown. The bar, therefore, operates to hold the support 246 against movement, it being understood that this support defines acentral opening which permits the shaft 242 to rotatewhile the support is held stationary.

The drive disc 250 carries a camming member 264 which operates to depress the bar 254 in opposition to the actionof spring 258 during each revolution of the disc. Accordingly, the cam frees a pin 262 from engagementwith the bar during each revolution of the disc whereby the support 246 is freed for movement for thedistance between pins during each revolution of the disc. The degree of intermittent movement of this support is, therefore, controlled by the number and spacing of the pins 262.

I Two or more wheels 266 are positioned between the drive disc 250 and support 246, and these wheels are mounted on axles 268 whereby the wheels are free to lr otate in response to the movement of the disc. When the support 246 is free for movement, the wheels 266 whereby assembly of wheels and axles is maintained 'in a stationary position. It has been found that theuse of wheels for transmitting drive in the manner illustrated'provides a highly efficient alternative to the friction drive arrangements previously described. In

this connection, it will be understood that the wheel drive arrangement can be substituted for any of the friction drive arrangements previously discussed.

It will be appreciated that the various machanisms described herein provide highly unique arrangements for achieving the movement of displays, particularly in that the rotary display movement is intermittent without involving any complicated or expensive mechanisms. The structures of the invention thus accomplish a desired attractiveness without any requirement for expensive elements whereby large scale use of the arrangements is practical. Commercially available motors comprise, for example, a motor of the type shown in FIGS. 1, l4 and 15, manufactured by Hankscraft of Fort Atkinson, Wisconsin or Motion Dynamics of New York City, and a motor of the type shown in FIG. 12 manufactured by Vue-More of New York City. Where a friction drive is employed instead of drive transmitting wheels, virtually any material is usable including Masonite material, sandpaper, etc.

The basic parts of the invention comprising the cams or switches, stop bars and pins, supports and other structural members are efficiently formed from any inexpensive material including cardboard, wood, plastic or metal. Items such as springs and tubes may be obtained from common stock.

It will be understood that various changes and modifications may be made in the above described structures which provide the characteristics of the invention without departing from the spirit thereof, particularly as defined in the following claims.

That which is claimed is:

1. In a construction for supporting an intermittently moving display comprising a motor, a display support, and means connecting the motor to the support for imparting movement to the support, said motor including a continuously rotating drive member, the improvement wherein said means for connecting said motor to said support comprise at least two first stop members carried by said support and fixed in position relative thereto, at least one second stop member, means mounting the second stop member adjacent said support, said second stop member being mounted so that it is fixed against movement in the direction of movement of the display support and so that it is free for pivoting movement in a direction perpendicular to the direction of movement of the display support, means carried by the support for pivoting the second stop member back and forth between one position in the path of movement of the first stop members to hold the support against movement, and a second position out of said path of movement to permit passage of the first stop members past the second stop member and to thereby result in periodic movement of the support, said means for moving the second stop member comprising a cam located for engaging said second stop member to drive said second stop member from said one position to said second position each time the cam engages the second stop member.

2. A construction in accordance with claim 1 wherein said display moves an angular distance corresponding to the spacing between said first stop means each time said cam moves said second stop means away from said one position.

3. A construction in accordance with claim 1 including friction drive means between said drive member and said support whereby said drive member imparts thereof, said motor being automatically brought into operating contact with the batteries upon pivoting to the operating position.

6. A construction in accordance with claim 1 wherein said drive member and said support comprise flat plates positioned in overlying relationship with friction drive means interposed between the plates, said first stop means comprising pins extending downwardly from the support plate, said second stop means comprising a resiliently mounted arm normally located in the path of movement of said pins, said cam operating to depress said arm to temporarily move the arm out of said path of movement.

7. A construction in accordance with claim 1 including a second display support, and drive means interposed between said first mentioned support and said second support whereby movement of the first support imparts movement to the second support.

8. A construction in accordance with claim 7 wherein said drive means between said supports comprise gears operating to rotate the second support in a direction opposite the direction of movement of said first support.

9. A construction in accordance with claim 7 wherein said drive means between said supports comprise at least one wheel adapted to rotate said second support in a direction opposite the direction of rotation of the first mentioned support.

10. A construction in accordance with claim 1 wherein the drive member is directly connected to the drive shaft of said motor.

11. A construction in accordance with claim 1 including a main shaft for supporting said drive member, said motor being offset relative to the position of said main shaft, and means providing a driving connection between the shaft of said motor and said main shaft.

12. A construction in accordance with claim 11 wherein said main shaft comprises a tubular member, electrical leads extending through said tubular member, and a light attached at the end of said tubular member adjacent said support, said display being located on said support adjacent said light.

13. A construction in accordance with claim 1 including at least one wheel interposed between said drive member and said support whereby said drive member imparts movement to said wheel which in turn imparts movement to said support each time said cam moves said second stop means away from said one position.

14. A construction in accordance with claim 13 wherein said drive member and said support comprise flat plates positioned in spaced apart relationship with said wheel interposed between the plates, said first stop means comprising pins extending downwardly from the support plate, said second stop means comprising a resiliently mounted arm normally located in the path of movement of said pins, said cam operating to depress said arm to temporarily move the arm out of said path of movement. 

1. In a construction for supporting an intermittently moving display comprising a motor, a display support, and means connecting the motor to the support for imparting movement to the support, said motor including a continuously rotating drive member, the improvement wherein said means for connecting said motor to said support comprise at least two first stop members carried by said support and fixed in position relative thereto, at least one second stop member, means mounting the second stop member adjacent said support, said second stop member being mounted so that it is fixed against movement in the direction of movement of the display support and so that it is free for pivoting movement in a direction perpendicular to the direction of movement of the display support, means carried by the support for pivoting the second stop member back and forth between one poSition in the path of movement of the first stop members to hold the support against movement, and a second position out of said path of movement to permit passage of the first stop members past the second stop member and to thereby result in periodic movement of the support, said means for moving the second stop member comprising a cam located for engaging said second stop member to drive said second stop member from said one position to said second position each time the cam engages the second stop member.
 2. A construction in accordance with claim 1 wherein said display moves an angular distance corresponding to the spacing between said first stop means each time said cam moves said second stop means away from said one position.
 3. A construction in accordance with claim 1 including friction drive means between said drive member and said support whereby said drive member imparts movement to said support each time said cam moves said second stop means away from said one position.
 4. A construction in accordance with claim 1 wherein said motor comprises an electrically operated motor, a tubular support for said motor, and batteries mounted in said support for supplying power to said motor.
 5. A construction in accordance with claim 4 including a pivoting bracket supporting said motor, pivoting of said bracket away from the operating position of said motor, exposing the batteries for insertion and removal thereof, said motor being automatically brought into operating contact with the batteries upon pivoting to the operating position.
 6. A construction in accordance with claim 1 wherein said drive member and said support comprise flat plates positioned in overlying relationship with friction drive means interposed between the plates, said first stop means comprising pins extending downwardly from the support plate, said second stop means comprising a resiliently mounted arm normally located in the path of movement of said pins, said cam operating to depress said arm to temporarily move the arm out of said path of movement.
 7. A construction in accordance with claim 1 including a second display support, and drive means interposed between said first mentioned support and said second support whereby movement of the first support imparts movement to the second support.
 8. A construction in accordance with claim 7 wherein said drive means between said supports comprise gears operating to rotate the second support in a direction opposite the direction of movement of said first support.
 9. A construction in accordance with claim 7 wherein said drive means between said supports comprise at least one wheel adapted to rotate said second support in a direction opposite the direction of rotation of the first mentioned support.
 10. A construction in accordance with claim 1 wherein the drive member is directly connected to the drive shaft of said motor.
 11. A construction in accordance with claim 1 including a main shaft for supporting said drive member, said motor being offset relative to the position of said main shaft, and means providing a driving connection between the shaft of said motor and said main shaft.
 12. A construction in accordance with claim 11 wherein said main shaft comprises a tubular member, electrical leads extending through said tubular member, and a light attached at the end of said tubular member adjacent said support, said display being located on said support adjacent said light.
 13. A construction in accordance with claim 1 including at least one wheel interposed between said drive member and said support whereby said drive member imparts movement to said wheel which in turn imparts movement to said support each time said cam moves said second stop means away from said one position.
 14. A construction in accordance with claim 13 wherein said drive member and said support comprise flat plates positioned in spaced apart relationship with said wheel interposed between the plates, said first stop means comprising pins extEnding downwardly from the support plate, said second stop means comprising a resiliently mounted arm normally located in the path of movement of said pins, said cam operating to depress said arm to temporarily move the arm out of said path of movement. 